Creamy Croque Monsieur Bake

Experience the epitome of French comfort food with this divine Croque Monsieur Casserole. This isn’t just any breakfast bake; it’s a culinary masterpiece that marries the irresistible flakiness of croissants with the classic, savory notes of a traditional Croque Monsieur. Forget the ordinary bread; here, we elevate the experience by using buttery croissants, creating an incredibly rich, melt-in-your-mouth dish perfect for any meal. Imagine salty cured ham, lavish melted Gruyère, a whisper of piquant Dijon mustard, all enveloped in a creamy, milky béchamel sauce. It’s a symphony of textures and flavors that transitions effortlessly from a decadent breakfast or brunch to a fulfilling lunch or a simple, yet elegant, supper. C’est absolument magnifique!

The Allure of Croissant Croque Monsieur Casserole

The Croque Monsieur, a quintessential French café staple, is revered for its simplicity and exquisite taste. Traditionally, it features layers of ham and Gruyère cheese between slices of pain de mie (white bread), grilled to perfection, and often topped with a velvety béchamel sauce. But what if you could take this beloved sandwich and transform it into an even more luxurious, fuss-free, make-ahead casserole? That’s precisely what this recipe achieves by replacing the classic bread with light, airy, and utterly buttery croissants.

Using croissants isn’t just a substitution; it’s an upgrade. The delicate, flaky layers of the croissant soak up the rich egg custard and béchamel sauce beautifully, creating an unparalleled melt-in-your-mouth texture that ordinary bread simply cannot replicate. Each bite offers a harmonious blend of savory ham, nutty cheese, and the subtle tang of Dijon, all brought together by the creamy embrace of the béchamel. This casserole provides all the comforting flavors of the original sandwich in an impressive, shareable format that’s ideal for gatherings or a special family meal.

A Brief History of the Croque Monsieur

The Croque Monsieur first appeared on Parisian café menus in the early 20th century. Its name literally translates to “crunch mister,” referring to the satisfying crispness of the toasted bread. It quickly became a popular light lunch or snack, celebrated for its hearty and satisfying nature. Over the years, countless variations have emerged, but the core elements of ham, cheese, and grilled bread remain iconic. This casserole version pays homage to its origins while offering a fresh, modern, and undeniably indulgent twist. It embraces the spirit of French culinary innovation, proving that even classics can be reimagined to delightful effect.

Why This Casserole is a Game Changer

Beyond its exquisite taste, this Croque Monsieur Casserole offers incredible convenience, particularly for entertaining. The beauty of this recipe lies in its make-ahead potential. Both the croissant base and the béchamel sauce can be prepared the night before, allowing for a stress-free morning when guests arrive or when you simply want to enjoy a leisurely weekend. The overnight chill time allows the croissants to thoroughly absorb the egg and milk mixture, resulting in a custardy interior that holds its shape beautifully while remaining incredibly tender.

This dish is also remarkably versatile. While its richness makes it perfect for a festive brunch or a holiday breakfast, its savory profile means it’s equally delightful as a hearty lunch with a side salad or a comforting dinner on a chilly evening. It’s the kind of dish that adapts to your needs, always delivering a satisfying and memorable experience. The combination of classic French flavors with a practical casserole format truly makes it a game-changer for home cooks and connoisseurs alike.

Croque Monsieur Casserole

4.55 / 11 votes

Croque monsieur—that perennial French classic—is the little black dress of the bistro set. Here we’ve given it a string of pearls, if you will, by making it a breakfast bake and using croissants. This is insanely rich, so a small piece goes a long way. (Or in our house, a not-so-long way.)

David Leite

Print

Course
Breakfast

Cuisine
French

Servings

10
servings

Calories

556
kcal

Prep Time

15 minutes
minutes

Cook Time

1 hour
hour

Chill

8 hours
hours

Total Time

9 hours
hours
15 minutes
minutes

Equipment

• 9-by-13-inch (23-by-33-cm) casserole dish

Ingredients

For the croque monsieur casserole

• Butter, for the dish
• 7 large croissants, (about 1 pound | 500 g)
• Your favorite Dijon mustard
• 14 slices deli ham, (about 8 ounces | 230 g)
• 8 ounces Gruyère, Emmenthaler, Jarlsburg, or Swiss cheese, grated (about 2 cups)
• 8 large eggs
• 2 cups whole milk
• Salt and freshly ground white pepper

For the béchamel sauce

• 3 1/4 cups whole milk
• 5 tablespoons (2 1/2 oz) unsalted butter
• 5 tablespoons all-purpose flour
• Pinch ground nutmeg
• Salt and freshly ground black pepper

Instructions

Make the croque monsieur casserole

• Butter a 9-by-13-inch (23-by-33-cm) casserole dish generously. This step is crucial to prevent sticking and to add a rich, buttery flavor to the bottom crust of your casserole.
• Carefully slice each croissant lengthwise, but not all the way through, creating a pocket. Gently spread a thin layer of your favorite Dijon mustard on the inside of each croissant. The mustard adds a zesty counterpoint to the rich ham and cheese.
  
• Tuck 2 slices of deli ham and approximately 1/4 cup of grated cheese inside each mustard-slathered croissant. Be generous with the filling, ensuring a delightful surprise in every bite.
  
• Cut each filled croissant into quarters. Arrange these pieces artfully in the prepared casserole dish. Don’t be afraid to turn them different ways to create an inviting visual appeal, allowing some of the savory ham and melted cheese to peek through the flaky layers.
  
• In a large bowl, whisk the large eggs until well blended. Gradually pour in the whole milk, continuing to whisk until the mixture is fully combined. Season this custard lightly with salt and freshly ground white pepper. White pepper is often preferred in béchamel-based dishes to avoid visible black specks.
• Evenly pour the egg and milk mixture over the croissant pieces in the casserole dish. Gently press down on the croissants with your hands or the back of a spoon to ensure every piece is thoroughly saturated with the liquid. This is key for a tender, custardy interior. Cover the dish tightly with plastic wrap and refrigerate overnight. This crucial chilling period allows the croissants to fully absorb the custard, preventing a dry casserole.
  

Make the béchamel sauce

• In a medium saucepan set over medium heat, gently warm the whole milk until a thin skin just begins to form on the surface. Be careful not to let it boil, as scorching the milk can alter its flavor. Warming the milk ensures a smooth béchamel without lumps.
• Simultaneously, in another medium saucepan over medium heat, melt the unsalted butter. Once melted, add the all-purpose flour to the butter and stir constantly with a whisk to create a roux. Continue cooking and stirring for about 2 minutes, until the mixture begins to bubble and smells slightly nutty, but without browning. This cooks out the raw flour taste.
• Slowly, in a steady stream, pour the warm milk into the roux, whisking vigorously the entire time to prevent any lumps from forming. Bring the mixture to a boil, then immediately reduce the heat to low and let it simmer. Continue to whisk gently until the béchamel thickens to a coating consistency, which typically takes an additional 2 to 3 minutes. Season the sauce generously with a pinch of ground nutmeg, salt, and freshly ground black pepper to taste.
• Pour the finished béchamel sauce into a clean container. Press plastic wrap directly against the surface of the sauce. This prevents a skin from forming as it cools. Allow it to cool completely to room temperature, then refrigerate overnight alongside your casserole base.

Assemble the casserole

• The next morning, remove both the casserole dish and the béchamel sauce from the refrigerator about 30 minutes before you plan to bake. This allows them to come closer to room temperature for more even cooking. Preheat your oven to 350°F (175°C).
• Uncover the casserole dish and place it on a foil-lined rimmed baking sheet. The foil will catch any potential drips or overflows, making cleanup easier. Use a whisk to stir the chilled béchamel sauce vigorously until it loosens and becomes smooth again. Evenly spread this creamy sauce over the entire top of the croissant casserole. Finally, sprinkle with the remaining grated cheese, ensuring a decadent, cheesy crust.
• Bake the casserole in the preheated oven for approximately 50 to 55 minutes, or until it is beautifully puffed up, golden brown on top, and bubbly around the edges. A delightful aroma will fill your kitchen, signaling that it’s nearly ready.
  
• Serve this magnificent Croque Monsieur Casserole immediately, while it’s still warm and the cheese is gloriously gooey.

Notes

For best results, use day-old croissants if possible, as they tend to absorb the custard better without becoming soggy. If using fresh croissants, you can lightly toast them in the oven for a few minutes before slicing to firm them up.

Don’t skimp on the quality of your ham and cheese. A good quality deli ham and a flavorful Gruyère will truly elevate this dish. Other suitable cheeses include Emmenthaler, Jarlsburg, or a robust Swiss.

Adjust seasoning to your preference. Remember that ham can be salty, so taste the egg mixture and béchamel before adding too much salt.

An LC Original

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Nutrition

Serving:
1 portion


Calories:
556 kcal


Carbohydrates:
31 g


Protein:
25 g


Fat:
37 g


Saturated Fat:
20 g


Trans Fat:
1 g


Cholesterol:
252 mg


Sodium:
727 mg


Fiber:
1 g


Sugar:
12 g

Nutrition information is automatically calculated, so should only be used as an approximation.

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Expert Tips and Variations for the Perfect Casserole

This Croque Monsieur Casserole is already a standout, but a few expert tips and optional variations can make it even more exceptional and adaptable to your needs.

Serving Suggestions

While the casserole is a complete meal in itself, it pairs beautifully with certain accompaniments. For a brunch setting, a fresh green salad with a light vinaigrette (like Joan Hunter Mayer suggests with butter lettuce, avocado, pistachios, orange segments, and fresh herbs) offers a refreshing contrast to the richness of the dish. A simple fruit salad or a side of crispy bacon can also complement it wonderfully. If serving for supper, consider a bowl of classic French onion soup or a hearty ratatouille for a full French-inspired feast. The versatility of this dish allows it to fit seamlessly into various meal plans and occasions.

Freezing and Reheating

Yes, this Croque Monsieur Casserole freezes beautifully! To preserve its quality, bake the casserole according to the instructions, then allow it to cool completely to room temperature. Wrap the cooled casserole tightly in plastic wrap, ensuring no air can get in, and then wrap it again securely with aluminum foil. Store it in the freezer for up to 2-3 months.

When you’re ready to enjoy it, transfer the frozen casserole to the refrigerator the night before to allow it to defrost gradually. Reheat the defrosted casserole in a preheated oven at 325°F to 350°F (163°C to 175°C) until the center reaches an internal temperature of 165°F (74°C) and it’s thoroughly warmed through and bubbly. Covering it loosely with foil for the first part of reheating can help prevent the top from browning too much.

Bread Alternatives

While croissants are undoubtedly the star of this particular casserole, you might wonder about other bread options. If croissants are unavailable or you prefer a different profile, enriched breads are your best bet. Think brioche or challah. These breads share a similar richness and slightly sweet, tender crumb that can stand up to the custardy mixture and complement the savory fillings beautifully. Avoid very dense or crusty breads, as they won’t absorb the liquid as well, and steer clear of overly airy white sandwich bread, which might become soggy. The goal is to maintain that luxurious, soft texture that makes this casserole so special.

Croque Monsieur Versus Croque Madame

For those curious about the subtle distinctions in French sandwich terminology, a classic Croque Monsieur is a grilled ham and cheese sandwich, often topped with béchamel. A Croque Madame, however, takes this delight a step further by adding a poached or lightly fried egg on top. The runny yolk of the egg mimics a lady’s hat, hence the “Madame.” In some regions of Normandy, it’s also known as a Croque à Cheval.

If you’re feeling adventurous and want to elevate your casserole experience, as our recipe tester Joan Hunter Mayer did, consider adding a perfectly cooked over-easy or poached egg to individual servings. This addition introduces another layer of richness and texture, truly transforming the dish into a Croque Madame casserole that will undoubtedly impress.

Another French cousin, the Monte Cristo, is similar but distinct. It’s a ham and Gruyère sandwich dipped in an egg custard (similar to French toast) and pan-fried, often served with jam or syrup for a sweet-savory combination. While delicious, it’s a different culinary journey from our rich béchamel-laden casserole.